JP2553014B2 - Intake system for fuel injection engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a fuel injection type engine in which fuel is supplied by a fuel injection nozzle.

[0002]

2. Description of the Related Art Conventionally, as an intake system for a fuel injection type engine, an air cleaner is arranged above the engine, an intake path extending from a cylinder head is connected to the air cleaner, and a fuel injection nozzle is attached to the intake path. There is. A fuel injection nozzle used in an intake device of a fuel injection engine of this type has a structure in which a fuel passage to which pressurized fuel is supplied is opened and closed by a solenoid valve, and the solenoid valve is operated for a predetermined time during an intake stroke. The fuel was measured and jetted by opening only the valve.

[0003]

However, as described above, the fuel injection nozzle provided with the solenoid valve has a relatively large tapping sound when the solenoid valve opens and closes, and the tapping sound leaks to the outside depending on the arrangement thereof. However, there was a problem of causing noise.

The present invention has been made to solve the above problems, and an object of the present invention is to prevent the noise from the fuel injection nozzle from being transmitted to the outside.

[0005]

SUMMARY OF THE INVENTION An air intake system for a fuel injection engine according to the present invention has an air cleaner above the engine.
The air intake port of the cylinder head to this air cleaner.
Connect the intake passage that extends from the combustion chamber through the
A throttle valve and a fuel injection nozzle that ejects fuel in the intake passage.
In the intake system of the fuel injection type engine having
Arrange the throttle valve and the fuel injection nozzle in this order from the upstream side.
From the throttle valve to the combustion chamber side opening in the intake passage
Form an approximately straight line and extend the axis of this intake passage
The angle between the line and the cylinder axis should be sharp.
The cylinder, the intake passage axis and the cylinder axis
Are V-shapes that open upward when viewed from the cam axis direction,
Around the cam shaft so that the axis of the intake passage is close to the vertical direction.
In a configuration inclined, the error Akurina, the intake passage
Intake passage connecting part and air cleaner element where the passage is connected
Comprising a housing part and housing this air cleaner element
Part above the head cover of the cylinder head.
The lower surface of the
The fuel injection nozzle as viewed in the cam axis direction.
Is surrounded by the upper part of the air cleaner, the air cleaner, and the intake passage.
It is arranged in an enclosed space .

[0006]

The noise generated from the fuel injection nozzle is blocked by the upper part of the engine, the air cleaner and the intake passage.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. FIG. 1 is a sectional view of a main part of a fuel injection engine that employs an intake system according to the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG. There is.

In these figures, 1 is a cylinder head of a four-stroke engine made of aluminum alloy, and a combustion chamber 2 is formed on the lower surface thereof. 1A is a cylinder body and 1B is a head cover. Inside the combustion chamber 2, a downward ventilation type intake passage 4 is connected via three intake valves 3a to 3c, and an exhaust passage 6 is connected via two exhaust valves 5.

Reference numeral 7 is a valve mechanism for opening and closing the intake valves 3a to 3c and the exhaust valve 5, 7a is an intake cam shaft, and 7b is an exhaust cam shaft. Of the intake valves 3a to 3c, the intake valve 3b located at the center is formed to have a larger diameter than the intake valves 3a and 3c located on both sides, as shown in FIG. Reference numeral 5a is a water jacket for cooling the combustion chamber 2, and 5b is an ignition plug provided in the center of the combustion chamber 2.

The intake passage 4 extends from a port 8 formed in the cylinder head 1 to an intake pipe 9, a throttle valve 10 and a bell mouth 11.
Connect to the air cleaner 12 via
It communicates with the atmosphere from 12. Also, this intake passage
4 is a substantially straight line from the throttle valve 10 to the combustion chamber 2 side opening
An extension line of the axis line Cp of the intake passage 4 which is formed
So that the intersecting angle between the cylinder axis Cc and the cylinder axis Cc is an acute angle.
I am configuring. The cylinder of this engine is shown in FIG.
As shown in, the axis Cp of the intake passage 4 and the cylinder axis C
c is a V-shape that opens upward when viewed from the cam axis direction.
So that the axis Cp of the intake passage 4 is close to the vertical direction.
It is configured to incline around the axis . The Airk
As shown in FIG. 1, the liner 12 includes the bell mouth 11
Of the intake passage connecting portion 12a to which the air cleaner element and the air cleaner element are connected.
Element 12b for accommodating the air cleaner element
And 12c. This air cleaner element
The housing 12c is disposed above the head cover 1B.
The lower surface of the head cover 1 from the intake passage connecting portion 12a.
It is formed so as to be unevenly distributed on the B side.

Reference numeral 13 is a fuel injection nozzle provided in the intake pipe 9. Incidentally, the fuel injection nozzle 13 is one in which, as is conventionally known, the gasoline in the fuel passage pressurized to about 2 kg / cm ² is metered and ejected by an electromagnetic valve which is opened only for a predetermined time during the intake stroke of each cylinder. Is. As shown in FIG. 1, the fuel injection nozzle 13 is provided in a space S that is substantially surrounded by the intake pipe 9, the throttle valve 10, the bell mouth 11, the air cleaner 12, and the upper portion of the engine when viewed in the crankshaft direction. It is located in. The upper part of the engine is composed of a cylinder head 1 and a head cover 1B.

Port 8 formed in cylinder head 1
As shown in FIG. 2, a centrally short branch passage 1b is provided side by side in the cam axis direction by two partition walls 1a, 1a from an opening 8a that opens to the side surface of the cylinder head, and is arranged on both sides thereof. It is branched into three with a slightly long branch passage 1c, and the downstream ends thereof communicate with the inside of the combustion chamber 2 via the three intake valves 3a to 3c.

As shown in FIG. 2, the port 8 has a center Cp at the upstream end of the intake air flow that is the cylinder center Cc.
On the other hand, it is offset by D toward the intake valve 3c side (right side in FIG. 2), and is formed so as to gradually widen from the upstream end toward the downstream side. More specifically, the inner wall 8b of the port 8 connected to the intake valve 3c
Extends from the upstream end in a direction substantially orthogonal to the cam shaft in the plan view shown in FIG. Further, the inner wall 8c of the port 8 connected to the intake valve 3a is inclined so as to gradually separate from the inner wall 8b toward the downstream side of the intake flow.

The partition walls 1a, 1a provided in the port 8 are formed so as to be slightly inclined so as to be substantially along the inner walls 8b, 8c.
2 is the partition wall 1a on the right side of FIG.
It is formed slightly longer in the flow direction of intake air. The lengths of these partition walls 1a, 1a are set so that the distance between the upstream end of each partition wall 1a and the injection port 15 of the fuel injection nozzle 13 described later is substantially equal.

That is, in the intake stroke, 3 in port 8
Of the two branch paths 1b, 1c, 1c, intake air linearly flows into the branch path 1c located on the right side and the central branch path 1b in FIG. 2 from the upstream side of the port 8 to the branch path 1c located on the left side. Flows in with the flow direction changed to the cam axis direction. Since the upstream end of the port 8 is offset to the right with respect to the cylinder axis as described above, the right branch passage 1c and the central branch are provided in the right half of the combustion chamber 2 in FIG. Intake air flows in from the passage 1b at a relatively high flow rate. For this reason, in the intake stroke, a swirling flow of intake air clockwise in FIG. 2 is generated in the combustion chamber 2. This swirl flow will be referred to as swirl below.

At this time, the left and right branch paths 1c,
Because of the inflow of intake air from 1c, a vertical swirling flow swirling around an axis parallel to the cam axis direction (clockwise in FIG. 1) is also generated in the combustion chamber 2. This swirling flow is hereinafter referred to as tumble. This tumble is combustion chamber 2
As shown in FIG. 1, the left and right branch paths 1 are generated inside.
This is caused by the difference in the inclination angle with respect to the cylinder axis and the curvature of the curved portion connected to the combustion chamber 2 between c and 1c and the central branch passage 1b.

That is, the inclination angle with respect to the cylinder axis is larger in the left and right branch passages 1c, 1c than in the central branch passage 1b, and the curvature of the curved portion is branched in the left and right branch passages 1c, 1c. It is gentler than the road 1b. For this reason, the intake air passing through the branch passage 1c has a large amount of flow along the hole wall surface on the outer peripheral side of the curved portion due to the inertia and flows into the combustion chamber 2 obliquely, and most of the intake air is taken. The flow direction is changed to the exhaust valve 5 side in FIG. 1 by hitting the valve body of the valve 3c. The intake air whose flow direction is changed in this way flows in the cylinder axial direction along the peripheral wall of the cylinder, and a clockwise swirling flow is generated in FIG.

On the other hand, the intake air passing through the central branch passage 1b flows into the combustion chamber 2 so that the direction of flow of the intake air passing through the left and right branch passages 1c, 1c is downward of the cylinder, and the intake valve 3b.
1 is made to flow toward the side opposite to the exhaust valve 5 in FIG. The intake air that has flowed into the combustion chamber 2 from this branch passage 1b is shown in FIG.
In the combustion chamber 2
However, since the flow rate of the intake air that is the clockwise swirling flow is large, tumble occurs in the combustion chamber 2 as described above.

The fuel injection nozzle 13 is connected to each branch 1
Two injection ports 15, 1 arranged in parallel in the arrangement direction of b, 1c
5, and the injection ports 15 and 15 are adjacent to each other, the partition wall 1a,
It is opened toward 1a. More specifically, the fuel injection nozzle 13 is positioned on the center Cp line on the upstream side of the port 8, and the center of the injection range of the fuel injected from both injection ports 15 and 15 is directed to the central intake valve 3b. There is. In addition, the two injection ports 15 and 15 and the partition wall 1
Distances A and B from a and 1a are substantially equal. Injection opening 15 and the partition wall 1a, the relationship between 1a In this way, fuel
The fuel injected from the injection ports 15, 15 of the material injection nozzle 13
Particles of fuel that are not atomized hit the partition wall 1a and burn
Direct injection to the spark plug 5b in the center of the chamber is eliminated.
Also, from one injection port that points to the center of the central branch
Compared to the case of injecting the entire amount of fuel,
If the divergence angle is the same, the amount of
As the fuel flowing into the crossroads 1c, 1c increases,
The fuel flowing into the branch passage 1b is reduced.

Next, the operation of this embodiment will be described. First, when the engine is operating, the three intake valves 3a are
When 3 c are simultaneously opened, the negative pressure of the intake air in the combustion chamber 2 spreads into the intake passage 4, the air is sucked from the air cleaner 12, the throttle valve 10 measures the air, and the intake pipe 9 discharges the fuel from the fuel injection nozzle 13. The ejected fuels are mixed and become a mixture, which is sucked into the combustion chamber 2. At this time, the fuel injection nozzle 1
From the relationship that the center of the injection range of the fuel injected from both injection ports 15 of 3 is directed to the central intake valve 3b,
The fuel is supplied to the branch passages 1c, 1c on both sides substantially evenly.
That is, when the air-fuel mixture is sucked into the combustion chamber 2 through the port 8, swirls and tumbles are generated in the combustion chamber 2 as described above, and the air-fuel mixture is distributed substantially evenly throughout the combustion chamber 2. Combustion is performed in the state.

On the other hand, when the fuel injection nozzle 13 ejects fuel, a tapping sound is produced from the internal solenoid valve. This tapping sound is generated by the intake pipe 9 surrounding the fuel injection nozzle 13, the throttle valve 10,
It will be blocked by the bell mouth 11, the air cleaner 12, and the upper part of the engine.

Therefore, the tapping sound of the solenoid valve generated from the fuel injection nozzle 13 is unlikely to leak to the outside. In addition, the intake
A substantially straight line from the throttle valve 10 to the combustion chamber side opening in the passage 4
And the extension of its axis Cp is the cylinder axis
Since it is configured to intersect the line Cc at an acute angle, the intake resistance is
Get smaller. Furthermore, the axis Cp of the intake passage and the cylinder shaft
V-shaped line Cc opens upward when viewed in the camshaft direction
So that the intake passage axis Cp is close to the vertical direction.
The cylinder is configured to be tilted, and above the intake passage
Air cleaner element of air cleaner 12 connected to the end
The housing 12c is provided above the head cover 1B.
From the intake passage connecting part 12a of the air cleaner 12
Since it is unevenly distributed to the head cover 1B side, the fuel injection nozzle
While securing the space for arranging 13, the intake system member
Horizontal length orthogonal to the cam axis of the included engine
(The length in the left-right direction in FIG. 1) becomes shorter. this
Forms the intake passage 4 in a straight line and extends it vertically.
In the case that the intake pipe 9 and the cylinder head are
Space where fuel injection nozzle 13 can be installed
, And tilting the cylinder,
The air cleaner 12 at the top of the air passage is large in the horizontal direction.
Although it overhangs, the intake passage axis Cp from the vertical direction
Inclining in the direction away from the cylinder head 1
Therefore, compared to the case described above,
The amount of overhang of the LINA 12 in the horizontal direction decreases.
The air cleaner element housing 12c
Because it can be placed in the dead space above the bar 1B.
It Moreover, the air cleaner 12 is constructed as described above.
Then, the air cleaner element accommodating portion 12c is moved to the horizontal position.
The volume can be increased without increasing the size in the direction.
Besides, if the intake passage 4 is formed into a substantially straight line,
Position where the liner 12 is largely separated from the cylinder head 1.
However, in the present invention, the air
The lean element accommodating portion 12c connects the fuel injection nozzle 13
Since it is surrounded from above, the fuel injection nozzle 13
Noise becomes even harder to leak.

In addition, the fuel is injected from the fuel injection nozzle 13.
Of the fuel that has not been atomized hits the partition wall 1a,
No direct injection to the spark plug 5b in the center of the combustion chamber
Then, the air-fuel mixture in the center of the combustion chamber 2 (around the spark plug 5b)
It does not get darker than other parts. Also, the central branch road
The entire amount of fuel is injected from one injection port that points toward the center of
Compared with the case where it is made, the spread angle of the injected fuel is the same
Then, out of the three branch paths, flow to the branch paths 1c, 1c on both sides.
Since the amount of fuel to enter can be increased, the outer circumference of the combustion chamber 2
The air-fuel mixture flowing into the section becomes thicker. Therefore,
So that the air-fuel ratio is almost uniform over the entire area of the combustion chamber 2.
Combustion is stable because it can be supplied to.

[0024]

As described above, the intake system for the fuel injection type engine according to the present invention has the intake passage interposed between the upper portion of the engine, the air cleaner, and the engine and the air cleaner when viewed in the camshaft direction. Since the fuel injection nozzle is arranged in the space substantially surrounded by, the noise generated from the fuel injection nozzle is blocked by the engine upper part, the air cleaner and the intake passage .

Therefore, it is possible to suppress the noise of the fuel injection nozzle from leaking outward. Also, the intake passage
Of the throttle valve to the combustion chamber side opening are formed in a substantially straight line
And the extension of the axis intersects the cylinder axis at an acute angle.
Since it is configured so that the intake resistance is small,
An intake device capable of achieving high output can be obtained. In addition, intake air
The axis of the road and the cylinder axis are upward when viewed in the cam axis direction.
It has a V-shape that opens to the front and the intake passage axis is close to the vertical direction.
Inclining the cylinder so that
Air cleaner for the air cleaner connected to the upper end of the intake passage
The element housing is arranged above the head cover and
Head cover from the air passage connection part of the air cleaner
Since it is unevenly distributed to the side, the space where the fuel injection nozzle is installed
The engine including the intake system members should be
The horizontal length orthogonal to the cam axis is shortened. this
Forms the intake passage in a straight line and extends it vertically.
The intake passage and cylinder head
Secure a space where the fuel injection nozzle can be placed
Tilt the cylinder to prevent it from reaching the top of the cylinder or the intake passage.
The air cleaner etc. on the edge may greatly protrude in the horizontal direction.
However, the intake passage axis should be
In the case described above by tilting in the direction away from
Horizontal direction of the cylinder top and air cleaner, etc.
When the amount of overhang decreases, the air cleaner
To the dead space above the head cover
This is because it can be installed . Besides, the air cleaner
With this configuration, the air cleaner element housing
The volume should be large without increasing the size in the horizontal direction.
In addition to being able to
Position where the air cleaner is separated from the cylinder head
However, in the present invention, the air
The lean element housing encloses the fuel injection nozzle from above.
Noise from the fuel injection nozzle
It becomes difficult to leak. Therefore, according to the present invention, the engine
The noise of the fuel injection nozzle is outward while achieving high output
Can be suppressed from leaking to the
Fuel injection nozzle in size in the horizontal direction of the engine was
This can be achieved while ensuring the installation space.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a fuel injection engine that employs an intake device according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

[Explanation of symbols]

 1 Cylinder Head 4 Intake Passage 9 Intake Pipe 10 Throttle Valve 11 Bellmouth 12 Air Cleaner 13 Fuel Injection Nozzle S Space

Claims (1)

(57) [Claims] 1. An air cleaner is arranged above an engine, and an intake port of a cylinder head is attached to the air cleaner.
Connect the air intake passage extending from the combustion chamber through this inlet passage
During road, and throttle valve, an intake system for a fuel injection engine having a fuel injection nozzle for injecting fuel, said diaphragm
Arranging the valve and the fuel injection nozzle in the order of upstream Karako Ri, before
A straight line from the throttle valve to the combustion chamber side opening in the intake passage
And the extension of the axis of the intake passage
Configured so that the angle with the Linda axis intersects at an acute angle,
Align the cylinder with the axis of the intake passage and the cylinder axis.
It has a V-shape that opens upward when viewed from the
Inclined around the cam axis so that the axis of the road is close to the vertical direction
And the intake passage is connected to the air cleaner.
Intake passage connecting part and air cleaner element accommodating part
And the air cleaner element housing
The lower surface of the Linda head, which is located above the head cover
Is unevenly distributed on the head cover side from the intake passage connecting portion,
The fuel injection nozzle is substantially surrounded by the upper part of the engine when viewed in the cam axis direction , the air cleaner, and the intake passage .
An air intake device for a fuel injection engine, which is arranged in a space .